Phenolics in Food and Nutraceuticals is the first single-source compendium of essential information concerning food phenolics. This unique book reports the classification and nomenclature of phenolics, their occurrence in food and nutraceuticals, chemistry and applications, and nutritional and health effects. In addition, it describes antioxidant activity of phenolics in food and nutraceuticals as well as methods for analysis and quantification. Each chapter concludes with an extensive bibliography for further reading. Food scientists, nutritionists, chemists, biochemists, and health professionals will find this book valuable.

Phenolics in food and nutraceuticals

There is increasing worldwide demand for proteins of both animal and plant origin However, animal proteins are expensive in terms of both market price and environmental impact Among alternative plant proteins, sunflower seeds are particularly interesting in view of their widespread availability in areas where soy is not or only sparsely produced Compared with other sources of vegetable proteins, sunflower seeds have been reported to have a low content of antinutritional factors Although the absence of these factors is important, the functionality of the protein preparations will mainly determine their applicability This review provides detailed information about sunflower seed composition and processing, including processes to remove phenolic compounds from meals The main part of the review concerns the structure and functionality of the two major protein fractions, helianthinin and 2S albumins Regarding functionality, emphasis is on solubility, thermal behaviour and surface activity Protein structure and functionality are discussed as a function of extrinsic factors such as pH, ionic strength, temperature and the presence of other seed components, particularly chlorogenic acid In addition, sunflower proteins are compared from a structural and functional point of view with other plant proteins, particularly soy proteins

Sunflower proteins: overview of their physicochemical, structural and functional properties

Crop germplasm collections are valuable resources for ongoing plant breeding efforts. To fully utilize such collections, however, researchers need detailed information about the amount and distribution of genetic diversity present within collections. Here, we report the results of a population genetic analysis of the primary gene pool of sunflower (Helianthus annuus L.) based on a broad sampling of 433 cultivated accessions from North America and Europe, as well as a range-wide collection of 24 wild sunflower populations. Gene diversity across the cultivars was 0.47, as compared with 0.70 in the wilds, indicating that cultivated sunflower harbors roughly two-thirds of the total genetic diversity present in wild sunflower. Population structure analyses revealed that wild sunflower can be subdivided into four genetically distinct population clusters throughout its North American range, whereas the cultivated sunflower gene pool could be split into two main clusters separating restorer lines from the balance of the gene pool. Use of a maximum likelihood method to estimate the contribution of the wild gene pool to the cultivated sunflower germplasm revealed that the bulk of the cultivar diversity is derived from two wild sunflower population genetic clusters that are primarily composed of individuals from the east-central United States, the same general region in which sunflower domestication is believed to have occurred. We also identified a nested subset of accessions that capture as much of the allelic diversity present within the sampled cultivated sunflower germplasm collection as possible. At the high end, a core set of 288 captured nearly 90% of the alleles present in the full set of 433, whereas a core set of just 12 accessions was sufficient to capture nearly 50% of the total allelic diversity present within this sample of cultivated sunflower.

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Genetic diversity and population structure in cultivated sunflower and a comparison to its wild progenitor, Helianthus annuus L

1. Studies were made on the lysine content of casein reacted with caffeic acid oxidized aerobically under alkaline conditions of enzymically with tyrosinase (EC 1. 14. 18. 1). 2. Loss of fluorodinitrobenzene (FDNB)-reactive lysine was rapid at pH 10 and increased with time and the temperature of the reaction, with concentration of caffeic acid and with the oxygenation of the mixture. In presence of the enzyme mushroom tyrosinase, maximum reduction of reactive lysine occurred at pH 7 and was dependent on the reaction time and on the concentration of caffeic acid. 3. Reaction of alpha-formyl-LO-[U-14C]lysine with caffeic acid at pH 10 showed the rapid formation of five reaction products which appeared to polymerize gradually as the reaction progressed. 4. The nutritionally available lysine content of the casein-caffeic acid mixtures, as assayed with rats, was reduced after both alkaline and enzyme reactions, as were faecal digestibility, net protein ratio and net protein utilization. Biological value however was not reduced. 5. In metabolic studies using goat milk casein labelled with L-[3H]lysine and reacted with caffeic acid in the same way, the lysine-caffeoquinone reaction products were not absorbed by the rat but were excreted directly in the faeces. 6. The importance of the reaction of proteins with caffeoquinone and chlorogenoquinone (formed by the oxidation of caffeic and chlorogenic acids respectively) is discussed in relation to the production of sunflower protein, leaf protein and other vegetable-protein concentrates.

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Protein-polyphenol reactions: 1. Nutritional and metabolic consequences of the reaction between oxidized caffeic acid and the lysine residues of casein

Sunflower flours and protein concentrates have potential food uses because of their high protein content, white color, bland flavor, and absence of antinutritive factors. Procedures have been developed for removal of chlorogenic acid which forms green and brown colors under alkaline pH, and selection for low chlorogenic acid cultivars is underway in plant breeding programs. Further research is needed on dehulling techniques and possible problems associated with high levels of sugars in sunflower flour. Sunflower flours and concentrates have excellent fat absorption, oil emulsification, and whipping properties. Wieners supplemented with sunflower products showed low shrinkage during the smokehouse treatment and low cooking losses due to high fat and water absorptions. Sunflower-supplemented wieners did score poorly in peelability and organoleptic tests. Sunflower proteins had an excellent amino acid balance except for low lysine content and, in feeding trials with rats, showed high protein efficiency ratios when blended with legume or meat proteins.

Chemical, functional, and nutritional properties of sunflower protein products.

Sunflowers (Helianthus annus L.) is one of the world's leading oilseed crops. Sunflower oil ranks second only to soybean oil in world vegetable oil production. Its high ratio of polyunsaturated fatty acids and its good stability characteristics make sunflower oil highly attractive for use as a cooking oil or in salad oils and margarine. Whole sunflower kernels and high protein sunflower meal can be incorporated into human food formulations. Topics of interest in the review will be the development of the sunflower crop in the United States, seed structure and composition, processing of the seed into oil and meal products, and marketing potential. Also, a review will be made of research on confectionery sunflowers and on the use of sunflower oil and meal in food products.

James A. Robertson

Papers

Use of sunflower seed in food products